Selective attention plays an important role in perception under a wide variety of conditions in which people are presented with too much information. Spatially selective attention allows observers to preferentially process a few of many simultaneously presented images or sounds. However, less is known about the role of temporally selective attention in allowing people to preferentially process information presented at specific times. The goals of this project are to describe the parameters of selective auditory attention directed to time periods, to explore the neural mechanisms involved in temporally selective attention, and to determine if temporally selective attention plays a role in efficient speech perception. In a series of five experiments, listeners will be directed to attend to specific times by individual symbolic cues, rhythms, and natural speech. Auditory temporally selective attention will be indexed by comparing event-related potentials (ERPS) elicited by physically identical non-target sounds presented at attended and unattended times. Just as studies of spatially selective attention have contributed to an understand of how people process large amounts of visual information presented simultaneously, the proposed studies can contribute to an understanding of how people process large amounts of rapidly presented auditory information. Continuous speech, one example of rapidly changing acoustic information, may require temporally selective attention for efficient processing. The proposed research will provide evidence about differential processing of sounds presented at attended and unattended times as well as how listeners select information for preferential processing. Therefore, it will contribute information of practical significance to the design and implementation of training programs for individuals in perceptually challenging environments, acquiring new skills, and with rapid processing deficits. Since temporal attention may be particularly important for speech perception, the results have important implications for improving communication skills in language-impaired children, adults with aging-related hearing lose, and individuals adjusting to perception through cochlear implants.